I don't know if I'm late discovering this, or if it's even actually a discovery... But since I updated to the 3.70.651.1 version of froyo I never get the 4G lag anymore(knock on wood)... I mean I used to hate having to reboot my phone 75% of the time when I used 4G. But since updating, I turn 4G on and off every day as needed, and I have not had the lag problem once yet. Is this the case for the rest of you guys(and girls)??